A Hologram Projection Cage, also called a Hologramatic Projection Cage or simply a Hologram Cage, was a hologram-related equipment that could be used to generate holograms outside of their normal field of projection, and exist outside of their spacecraft of origin, for extended periods of time. The cage was a fairly basic hologram-generating technology, compared to the much more mobile Light Bee which Rimmer would later come to use.